extractor exhaust manifold

[matt31]

i will soon be buying a r32 rb20det engine, gtr intercooler, r33 turbo and aftermarket computer for my r31 passage, and i was wondering weather to get an extractor exhaust manifold or to get the head ported and polished. if some has heard or had any experience with either of these mods advice would be very much appreciated.

[GTS-t VSPEC]

matt31,

In general the most gains will be found in the exhaust manifold, as that is where most of the airflow restriction is found, and a better flowing head with a factory exhaust manifold will net you very little gains.

That being said, if you are planning on using a factory r33 turbo then I wouldn't waste the money on the exhasut manifold. The turbo has just enough to support approx. 280-300rwhp, regardless of the exhasut manifold, although it would do it more efficiently.

I would suggest that you think about a bigger turbo and have an exhaust manifold made for that, then you would notice the gains. This is what I am doing.

See'ya:burnout:

[Steve]

Good call GTS-t VSPEC,

the R33 turbo isnt the most reliable piece of kit, in your situation, perhaps save the money that would be used for a manifold or port and see if you cant pick up a garrett bb turbo, or a highflow instead. With the stock turbo you still have the restriction of the turbine - so it would make better sense to go the turbo first, then manifold, then port/polish/match.

[GTS-t VSPEC]

Steve,

Yes that is the order I would do it, but with many bigger turbo's then the turbo and exhaust manifold need to be done together.

Matt31,

If you already have the turbo then use it until your bored with the power, then upgrade to something better along with the manifold. Port and polish it something for later to improve efficiency of your turbo.

See'ya:burnout:

[matt31]

thanks for the info but problem is that ive already bought the turbo, but i have heard good things about highflowing these turbos, what do u guys think.

[Cubes]

It really depends on how you drive if the turbo is reliable or not.

If you use it for quick squirts at the traffic lights then on a RB20DET the R33 turbo should handle 16psi no problems.

I've been running my R32 turbo on 16psi for general traffic light runs almost 6months now.

Isn't 300rwhp around 223rwkw... On a R33 Turbo?!?! Or did you mean flywheel?

[Steve]

280-300rwhp has and is being done regularly. It is my understanding that 300rwhp is on the limit of the turbo.

[GTS-t VSPEC]

Yeah 280-300rwhp is the limit of the factory turbo, doesn't matter what else you do you can't get much more than that.

I personally wouldn't suggest hi-flowing the turbo. I suggest running the turbo as is until you need more power then decide what is the best way to get your power. If your only after a bit more power then hi-flowing is ok, but if you want alot more power then a bigger turbo is the only way to go.

Remember it's not a race to get huge horsepower, enjoy the car, drive it and then upgrade the power.

See'ya:burnout: